Couple of questions/ideas: Does it have an onboard glow driver or remote? If so, try it without? What is your throttle servo/Have you tried a different one? Check/double check/triple check the connections at the receiver&battery.... maybe try a plastic clevis for the throttle arm? I doubt you're getting interference on just one channel, and only at high throttle - sounds more like a connection somewhere to me.... good luck, hope you find & post the culprit!